Instruction manual

DAC1 HDR Instruction Manual Rev I Page 18
Internal Settings
Removing Top Cover
The DAC1 HDR cover must be removed to
gain access to the jumpers. Do not attempt
to remove the faceplate or rear panel.
CAUTION: The DAC1 HDR contains static
sensitive components and should only be
opened by qualified technicians. Static
discharge may cause component failures,
may affect the long-term reliability, or
may degrade the audio performance. Use
a static control wrist strap when
changing jumper settings.
CAUTION:
• Disconnect AC power by unplugging
the power cord at the back of the
DAC1 HDR.
• Remove only the 8 screws holding the
cover (4 on each side).
• Do not remove any screws on front or
rear panels.
• Never remove the power entry safety
cover in the rear corner of the DAC1
HDR.
• Always connect a static-control wrist
strap to the chassis before touching
any internal component.
Low-Impedance Passive Pads
The XLR outputs are equipped with low-
impedance passive pads that may be used to
reduce the output levels while preserving the
full dynamic range of the DAC1 HDR. The
DAC1 HDR ships with the 20 dB pads
enabled.
TIP: When directly driving power
amplifiers and powered speakers, use
‘Variable’ mode and start with the
factory default 20 dB pad setting. If
necessary, change the pads so that
normal listening levels are achieved with
the ‘Volume Control’ above the 11 o’clock
position.
When the output pads are enabled, the
output impedance changes slightly, and the
maximum allowable cable length should be
reduced as shown in Table 1 (assuming 32
pF/foot and a maximum allowable loss of 0.1
dB at 20 kHz).
Table 1 - Cable Drive Capability
Balanced Output Drive Capability:
Attenuator
Output
Maximum
Loss in dB
Setting (dB)
Impedance
Cable (ft)
at 20 kHz
0 60 680 0.1
10 425 96 0.1
20 135 302 0.1
30
43
949
0.1
Unbalanced Output Drive Capability:
Output
Maximum
Loss in dB
Impedance
Cable (ft)
at 20 kHz
30
1360
0.1
TIP: To set the XLR outputs to typical
professional studio levels, set the pads
to 0 dB, and set the ‘Output Level Switch’
to ‘Calibrated’. The factory set
calibration levels of the XLR outputs are
+4 dBu at -20 dBFS. The RCA outputs
are calibrated to -10 dBV at -16 dBFS.